bt hdv



H. E. CURTIS.

CARBURETER.

APPLICATION FILED APR, 18. I917.

Patented July 15, 1919.

vsuanl FIGURE- 2 FIGURE 4- zaupg:

ATT RN -Y PATENT OFFICE.

HENRY E. CURTIS, OF SAN JOSE, CALIFORNIA.

CARI! UR-ETER.

Application filed April 18, 1917.

To (ZZZ whom it may concern Be it known that l, lilnunv 15. (loans, a citizen of the United States, and resident of San Jose, in the county of Santa (Tiara and State of California, have invented a certain new and useful Improvement in (larbuieters, of which the following is a specification.

llly invention relates to carbureters, and the object of my invention is to provide a carbureter of simple construction that can be easily and cheaply inanufactored; that is adapted to supply the proper mixture of air and fuel under any and all engine loads and speeds; that will supply a small quantity of a uniformly rich mixture for operating the engine at exceedingly low speeds; that will successfully and efficiently carburet the air with fuels of varying density; that will supply an initial charge of rich mixture to the engine when the same is turned over slowly and thereby permit the quick and easy starting of the engine.

A device whereby the above and other objects are attained is illustrated, by way of example, in the accompanying drawing and hereinafter described in detail.

In the drawing:-

Figure l is a longitudinal, sectional view through my improved carburetor.

Fig. 2 is a sectional view on line A A of Fig. 1 with a choke valve inserted.

Fig. 3 is an end view of the carhureter taken on line ()-C of Fig. 2.

Fig 4 is an elevation of the throttle.

Fig. 5 is a detail sectional view on line B--B of Fig. 2.

Similar characters of reference refer to similar parts throughout the several views.

At 1 is indicated the hollow cylindrical casing of the carbureter provided with air inlet 2 controlled at starting by choke valve 3, and discharge outlet +1 controlled by throttle 5. Cast integrally with body 1 is threaded flange 6 to which is screwed bowl 7 thereby forming float chambers in which is shown float 9 and fuel 10. Since any well known method of supplyiu fuel 10 and keeping the same at a coi'lstant evel in chamber 8 may be used. I do not show or describe devices for this purpose. At 11 is shown a Venturi tube having its inner surface in the form of a Specification of Letters Patent.

Patented July 15, 1919.

Serial No. 182,911.

short truncated cone 12 and a long trunrated cone 13 joined by a short throut-poition it, surface 12 being directed toward in let 2. The outer surface of tube ii is pro vided with a flang 1?) fitting closely in had}; 1 and concentric with throat-portion t-l,-the proportions of this flange preferably being such that its thickness longitudinally of the tube is in excess of its width. The inner end of tube 11 is provided with an annula surface l adapted to fit closely in body 1 a shown, the space between flange 15 and the inner edge of surface 16 forming an (open sion chamber 17.

A fuel nozzle is shown at l8 fitted in ra+ ing and secured in any appropriate uay i it) and passing through bore 20 in tube ll and having its discharge end positioned in substantially the center of tlwoat-prntion ll. The conduit 21 in nozzle 18 communicates, in this case, directly with the fuel 10 in chain her 8. At 22 are provided a plurality o f ori fices connecting chamber 17 with the interior of tube 11. The various elements aboride scribed are all positioned in fixed relation to each other.

An angularly projecting portion :12?- is formed as shown on the side of casing Z and the top of flange 6, and has a conduit bored lengthwise therethrough tn coun iuuw cate with discharge outlet 4 at a point fillid" cent throttle 5 so as to operate in aurzunu tion therewith when said throttle is closed or nearly closed, throttle 5 having a small opening formed therein as at 25 and substantially in alinement with said conduit. 2t when said throttle is closed. The outer end of conduit 24 is threaded to engage a threaded adjusting screw 26. At 27 is shown a second conduit bored vertically through portion 23 and communicating with conduit 24 and having a pipe 28 fixed in communication with its lower end, said pipe passing inwardly and downwardly so as to have permanent communication with fuel 10 in chamber 8 as shown. Expansion chamher 17 and air inlet 2 are connected by a, plurality of orifices 29 formed in flan e 15. At 30 is shown the carburetingehambe and at 31 is indicated the mixing chamber.

The parts indicated by numerals 23 to'28 inclusive form an auxiliary carhuretin de vice which is extremely ellective in starting the engine and in operating the same at very low speeds When the engine is turned over at starting, the throttle 5 and rholu valve 25 being! closed or nearly closed the suction through opening :25 draws a small amount ol air through tulie 11 and a small but proper tionally large anniunt of fuel from chamber 8 through conduits El? and 2-1 respectively. This rich mixture gives almost instant results. When the engine is started choke valve 3 is opened wide and throttle 5 is opened a distance, the increased load or speed now drawing the air through orifices 2: and throat portion l4 and fuel from thr nozzle 18 as well as a small umounl 01 fuel from conduit 'lln- How of fuel from con duit 2 inhconduit :44 is regulated by adjusiing eifl' ffl 2(5. lly the plulwl selling ol' sore-v Lit and thnollle Ii. l halifound, that l l'llll run a ma hine rquipprd nith this ill-xi si'iadily and E!l\)()l lll"f as l l(i-Vl} as three miles an liouix As throttle 5 is opened for greater speeds and loads this auxiliary car iiurcting de ice is reinicred inactive be .ansc ol' the reduced velocity of the mixture passing the discharge end of conduit W'hen the throttle is opened Wider as above forth the action is as follon s. The flow of air through throat-portion 14 draws fuel from nozzle 18 in the usual manner. The compensating air, however, is retarded in its passage through conduits E29 and orifices 22 on account of the large amount of surface with which it comes in contact In passing through conduits .29 the velocity of the air increased. As said air enters rhamher i? it immediately expands with the result that its velocity is reduced and its loreard mo tion checked. This process is repeated as the air passes through orifices 22 into the interior of tube 11. One result of this action is that when throttle 5 is opened sufficiently wide to permit fuel and air to be drawn throu h tube 11, a large number of small jets 0 compensating air are injected into the mixture thereby assisting materially in the vaporizing process, and carrying condensa tion back into the mixture. The orifices 22 perform these functions best when formed as shown and directed inwardly and forwardly toward the throttle 5 as the injected air then more readily moves forward with the mixture and does not tend to form a blanket over the throat-portion 14-.

It is manifest that if compensating air were allowed to flow into chamber 31 freely the suction through throabportion 14 would be reduced correspondingly and insullicient fuel to secure a proper mixture would be drawn from nozzle 18. If flange 15 were omitted or made as thin as the Wall or casing 1 there would he so little retarding of the air current as to be almost negligible, the

retarding being ell'crted entirely by orifices 22. l have found this l'elaiding lo lie insul" licient, but have discovered that ii conduits 2!.) are lenglliem-d somewhat the air is re larded in its passage tlierellirougli and nli stantially checked in its movemenl when ii expands in clnimlier lit and its l'orward movement. is again relaril il as it is drawn through orifices 22. By properly proportioning the number and size oi conduits 2!? lo chamber 17 and orifices 22 l have discovered that the flow of compensating air into chamber 31 may he properly proportioned at all times to the flow of fuel and air from carbureting chamber 30 While some carburetors use spring: coir trolled (lktVlIlLi for governing lliiil'n. ol lurl irom the nozzle, and olhrrr as! r ipro rating relics operated anlomatiml v liy ln iryiii lluid l l'i c in the 11th Emmi governing h flow ml fil'l l'rczn :iln m-ix lil nlllii e i: ilw llH'Wi'lll tional resistance oll'cicil ra nings ol proper: a l min; too oi an expansion chamlici, 'lioi securing the desired result. The word unbroken in the claims is used to designate an inclosing wall having no perforations or valve openings of any kind.

While I have shown and described one specific form of my invention, it is understood that changes in form, proportions, con strnction and operation may be made within the scope of the appended claims.

l claim 1. A carburetor comprising a cylinder tuning a valve controlled mixture outlet at one end the eof and an air inlct a! liar other end thcreo'h :1 "dentin-i tul e fixedly peel tinned therein intermediate said inlet and said outlet and provided with outwardly tending and spaced portions to engage said cylinder and form therewith an expansion chamber having an unbroken outer wall, one of said outwardly extending portions having a thickness greater than its width and provided with conduits forming open but re stricted communication between said expansion chamber and said air inlet, and said tube having a plurality of orifices formed therein connecting said expansion chamber with the interior thereof, and a fuel nozzle discharging into said tube and connected to a fuel. supply.

2. A carburetcr comprising a cylinder having a valve controlled mixture outlet at one end thereof and an air inlet at the other end thereof. a Venturi tube fixedly positioned therein intermediate said inlet and said outlet and provided with outwardly extending and spaced portions to engage said cylinder and form therewith an expansion chamber havin an unbroken outer well, one of said ontwar ly extending portions having a plurality of conduits formed therein to int-1:;

provide open but restricted connnunication between said ex'iansion chamber and said air inlet, and mill tube having a plurality of orifices formed therein to ronnect said expansion rhnmher with the interior thereof, said orifices being greater in number 11ml smaller in ClOSS-Sfittlflllill area than said c0nduits, and a fuel nozzle discharging into Said tube and connected to a fuel supply.

In testimony whereof I have hereunto :if- 10 fixed my signature this 11th day of April, 1917.

HENRY E. CURTIS. 

